A case of primary familial congenital polycythemia with a novel EPOR mutation: possible spontaneous remission/alleviation by menstrual bleeding.

A 10-year-old girl with persistent erythrocytosis and ruddy complexion was diagnosed with primary familial congenital polycythemia (PFCP) involving a novel heterozygous mutation of c.1220C>A, p.Ser407X in exon 8 of the erythropoietin receptor gene (EPOR). This mutation causes truncation of EPOR, resulting in loss of the cytoplasmic region, which is necessary for negative regulation of erythropoietin signal transmission. Genetic analysis showed that the mutated EPOR was inherited from her mother. Her mother had polycythemia and had undergone venesection several times when she was young, but her polycythemic state appeared to have resolved. Venesection was not needed to maintain Hct levels within normal range. For the case reported here, venesection was also conducted to maintain the blood Hct level below 50%. We observed that after the patient experienced menarche, the volume and frequency of venesection needed to maintain Hct level < 50% were clearly reduced compared with those before menarche. These findings suggest that, in female patients with this type of EPOR mutation, menstruation might reduce blood volume in a manner similar to venesection. Spontaneous remission of erythrocytosis may thus occur after the start of menstrual bleeding.